Key Control Points and Secrets of Biological Reactions in MBBR Process

Key Control Points and Secrets of Biological Reactions in MBBR Process

Summary

Control of influencing factors of MBBR process and control of MBBR biochemical process.

Key Control Points and Secrets of Biological Reactions in MBBR Process
By: Kate Nana
Post Date: March 31th, 2025
Post Tags:Key Control Points and Secrets of Biological Reactions in MBBR Process
MBBR process influencing factor control and process control

Core influencing factors and control methods of MBBR process：


1. Temperature control
Influence mechanism: Temperature directly affects microbial activity and biofilm metabolic rate.
Low temperature (<15℃) will reduce the activity of nitrifying bacteria, resulting in a decrease in ammonia nitrogen removal rate;
High temperature (>35℃) may cause excessive proliferation of heterotrophic bacteria and destroy the balance of the system.
2. Dissolved oxygen (DO) zoning control
Dissolved oxygen is an important factor affecting the removal of organic matter.
Especially when the purpose is to remove phosphorus and nitrogen, the concentration control of dissolved oxygen is particularly important. In different types of biofilm reactor processes, the mixed liquid forms aerobic, anoxic and anaerobic sections in the bioreactor in various forms.
Segment control targets:
Aerobic zone: DO ≥ 2 mg/L (to ensure COD degradation and nitrification reaction).
Anoxic zone: DO = 0.2 ~ 0.5 mg/L (denitrification and denitrification).
Anaerobic zone: DO ≤ 0.2 mg/L (activation of phosphorus-releasing bacteria).
Control range of DO in each section of the reaction pool
3. Mixed liquor sludge concentration (MLSS) management
Control range: MLSS in aerobic zone is recommended to be 3000~8000 mg/L (too high will easily cause accumulation, too low will result in insufficient treatment capacity).
Therefore, a moderate sludge concentration in the feed liquid should be maintained. Too high or too low will reduce the water flux.
4. pH adjustment
Ideal range: influent pH 6.5~8.5 (nitrification optimum pH=7.5~8.0).


Low temperature operation control (inlet water temperature <8℃)：


MBBR Process Flowchart
1.  When the influent water temperature is lower than 8℃, the activity of the activated sludge is affected to a certain extent. At this time, the effluent volume should be appropriately reduced to ensure that the organic matter in the sewage is fully degraded in the reaction tank, thereby ensuring the effluent water quality.

2.  In the season when the temperature changes suddenly, pay special attention to the effluent water quality. If the effluent water quality changes suddenly, reduce the appropriate effluent volume and increase the aeration time.

3.  During normal operation, disinfectants and disinfectants that inhibit microbial metabolism should be avoided from mixing into the biological reaction tank. Prevent the normal biological mechanism of microorganisms in the equipment from being destroyed, resulting in deterioration of the effluent.

4.  When the sewage contains a large amount of synthetic detergents or other foaming substances, a large amount of foam will appear in the biofilm reaction tank. At this time, water spraying can be used to solve the problem, but do not add defoamers containing oily substances to the reaction tank to remove the foam. Silicone series defoamers are also not allowed to be used.

Through refined management, the stability and impact resistance of the MBBR process can be significantly improved, ensuring the long-term and efficient operation of the sewage treatment system.